Until now, basically, no one has had any idea. By law, the U.S. census cannot ask questions about religion. There are also plenty of other difficulties in coming up with a number, starting with the difficulty in defining who is a Muslim: Does one include non-standard believers like Louis Farrakhan and the Druze? Or include those who converted to Islam but no longer practice it, like the jazz pianist McCoy Tyner (“At this point in my life, I am no longer a member of any organized religion”)?

Uncertainty has generated some wildly divergent numbers. In 1986, the Saudi embassy in Washington claimed 10 million Muslims. A large 1990 demographic survey counted 1.3 million. In 1998, a Pakistani paper put the number at 12 million. Even the usually authoritative “Yearbook of American and Canadian Churches” reflects this state of confusion: it found 527,000 American Muslims in 1996 and six times as many (3.3 million) in 1998.

The population of African-American converts to Islam is subject to yet wilder divergences, with figures bandied about that range from 10,000 to 4.5 million.

Needing some kind of consensus figure, Muslim organizations came up with a self-acknowledged “guestimation” of 6 million, which earlier this year they decided to increase to 7 million. These numbers were so widely adopted (even by this writer) that they acquired a sheen of authority. But repetition does not transform a guess into a fact.

The trouble with this number is a generic one; religious organizations commonly inflate their membership to enhance their voice in the public square. Samia El-Badrey, a specialist in Arab-American demography and head of the International Demographic and Economic Association, correctly notes that their data “tend to be higher than reality because the sources want to make sure their numbers are high.”

Fortunately, the smog of imprecision finally lifted last week, with the appearance of two authoritative studies by highly regarded demographers. Interestingly, they agreed on a very similar number, one much smaller than the old “guestimation.”

The American Religious Identification Survey 2001 carried out by the Graduate Center of the City University of New York polled more than 50,000 people and found the total American Muslim population to be 1.8 million.

Tom Smith of the University of Chicago reviewed prior national surveys and (in a study sponsored by the American Jewish Committee) found that the best estimate puts the Muslim population in 2000 at 1,886,000. With a nod toward figures supplied by Islamic organizations, Smith allowed that this number could be as high as 2,814,000 Muslims.

In other words, two authoritative studies carried out by scholars found that American Muslims number under 2 million – or less than one third of the hitherto-consensus number.

To this, the militant Islamic groups in Washington – widely but erroneously seen as representative of American Muslims – responded with predictable hyperbole. The Council on American-Islamic Relations furiously accused Smith’s report of working “to block Muslim political participation.” The American Muslim Council charged Smith with nothing less than trying to “deny the existence of four and a half million American Muslims” and blamed him for “tearing at the very heart of America.” The AMC also amusingly claimed that its own estimate of “more than seven million” Muslims came from the 2000 census figures – erroneously thinking that the census asks about religion.

Oh, and that’s the same AMC which in 1992 pressured a researcher named Fareed Nu’man to find 6 million Muslims in the country; Nu’man later testified that he counted just 3 million and was fired by the AMC when he refused to inflate his number above 5 million.

Why does the militant Islamic lobby insist on the 6-7 million figures? Because a larger number, even if phony, offers it enhanced access and clout. Convincing the Republican Party that Muslims number 8 million, for example, led to urgent calls from its chairman for “meeting with [Muslim] leaders,” something which becomes less of a priority when the Muslim population turns out to be much smaller.

Knowing the real number of Muslims will, most immediately, likely impede two militant Islamic efforts now under way: one (pushed by The Minaret magazine) to get Americans to acknowledge that their own misdeeds partially caused the atrocities of Sept. 11 and another (led by CAIR) to halt the U.S. military campaign in Afghanistan. The longer-range implications will be yet more significant.